How does a network transform one impedance to another?

The goal of an impedance matching network is to make a complex load (which has both resistive and reactive components) look like a pure resistance (usually 50 ohms) to the transmitter. To do this, the network first introduces a reactance that is equal and opposite to the load's reactance, effectively canceling it out. Once the reactive part is neutralized (a state known as a conjugate match), the network functions essentially like an RF transformer. It alters the remaining resistive part of the load to perfectly match the source resistance. Distractors mentioning "negative resistance" or "transconductance" are incorrect because those are properties of active components (like tunnel diodes or vacuum tubes). Impedance matching networks are built with passive components (inductors and capacitors) which only cancel reactance and transform resistance.